Electrical cable



tions of such insulating compounds.

UNITED STATES PATENT CEEicE.

HENRY A. CLARK, OF BOSTON, MASSACHUSETTS.

ELECTRICAL CABLE.

SPECIFICATION forming part of Letters Patent No. 310,879, dated January 20, 1885.

Application filed February 18, 1854.

T0 aZZ whom, it may concern:

Be it known that I, HENRY A. CLARK, of Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Electrical Cables, of which the following is a full, clear, and exact description.

This invention relates to a cable for tele phonic, telegraphic, and electric purposes generally, the object being to provide a cable in which leakage shall be prevented and inductive eifeets of any wire upon the others obviated so far as possible.

To these ends it consists in the cable con structed as more fully hereinafter described and claimed.

In the drawings, Figures 1 and are side views of a cable embodying the invention, while Figs. 2 and 4 are sections thereof on lines 4 4 and 6 6, respectively.

A is the core-wire of the cable, of any suitable size an. material, so that it is agood or fair conductor of electricity. Upon and around it are spirally wound the conductors B, each of which is provided with its own insulatingcoating Z), so that each is independently insulated from all the others and from the core-wire A. This insulation may be of any of the well-known insulating materials such as rubber, kerite, gutta-percha, &c., either alone or in any of the usual combina- Upon these wires B is laid a conducting-strip, G, which maybe spirally wound thereon, or laid or folded longitudinally, as may be desired. This strip 0 may be of foil, or of sheet metal thin enough to be flexible. This in turn is protected by the exterior covering, E, braided, spun, or woven thereon in any of the wellknown ways of applying a fibrous jacket or casing to wires. lVhen desired, however, to insulate the covering 0 and the interior cable more thoroughly than would be accomplished by this fibrous jacket or casing E, a covering of insulating material,D,of gutta-percha, kerite, or equivalent insulating compound, is first applied to and over 0, and the jacket or casing E applied upon the exterior thereof, as shown in Figs. 8 and 4.

(No model.)

In practice the wires 13 are used as the cir cuit-wires for conveying the impulses necessary for the desired signaling or communications, and A and C are connected tothe ground at each end by suitable electric conductors. In such construction the circuit-wires B are thoroughlyf insulated each from the others and from the air and other conducting mediums, so that leakage therefrom is practically avoided, while the inductive influence of any wire when in use is expended upon the wirecore A and metallic covering C, by which, they being in connection with the ground, the induced currents are conveyed to the ground, and the danger of disturbance of any wire by induction from another or the others is reduced to a minimum and in practice entirely obviated. At the same time the cable is flexible, and adapted to be used under any conditions, andin any position or relation, underground, overhead, orsubmarine.

I am aware that it is old to construct a cable with alternate groups of insulated and naked wires wound in opposite directions and with the naked wires connected to the earth; and also to make a single insulated conductor of a wire covered with an insulation and having a coating of foil upon such insulation, the foil in turn being covered by an insulating-coat; and also to make a cable having a core of anumber of wires surrounded by a series of insulated wires wound around the core of central wires, a covering being then wound around both to hold them in a rope, and also to apply a continuous close coating of guttapcrcha to a series of wires, hence I claim none of these things; but

. Vhat I do claim is 1. An electrical conducting-cable consisting of a central naked conducting-core, a sesies of independently-insnlated wires wound spirally therearound, a conductingstrip of foil or thin sheet metal applied thereover, and a braided or woven fibrous jacket inelosing and protecting the wires and foil, the inner core and the foil or sheet metal being adapted to be connected to the earth, substantially as described.

2. An electrical conducting-cable consist ing of a naked conducting-core, series of In testimony whereof I have hereunto set 10 wires each independently insulated and spimy hand in presence of two subscribing witrally wound around the core, a strip of foil nesses.

or other thin sheet conductor wound or folded thereupon, a coat of insulating material placed over and around the foil or sheet conductor, and a braided or woven fibrous \Vitnesses:

protecting jaeketinclosing the whole struct- EDWIN XV. BROWN, ure, substantially as described. VM. F. BELLOWS.

HENRY A CLARK. 

